ARSON TRIPLED BETWEEN 1964 AND 1974. CURRENTLY A NATIONAL EPIDEMIC, ARSON CAUSED ESTIMATED PROPERTY LOSSES IN 1974 THAT RANGED FROM $616 MILLION TO $1.3 BILLION. ACCORDING TO CONGRESSIONAL INVESTIGATORS, ARSON-FOR-PROFIT IS THE FASTEST GROWING CRIME IN THE COUNTRY, ALTHOUGH THE NATURE OF THE CRIME MAKES ITS INCIDENCE DIFFICULT TO ESTIMATE. MOREOVER, THE SCIENTIFIC STUDY OF ARSON AND ARSONISTS' BEHAVIOR HAS BEEN INCOMPLETE, WITH THE FEW SYSTEMS STUDIES PRODUCING CONTRADICTORY DATA DRAWN FROM BIASED SAMPLE POPULATIONS. PROBLEMS THAT RESEARCHERS HAVE BECAUSE OF LOW ARSON APPREHENSION RATES, LEGAL CONSTRAINTS IN INFORMATION DISCLOSURE, METHODS OF LEGALLY DISPOSING OF ARSON CASES, AND UNRELIABLE STATISTICS SOURCES ARE DISCUSSED. IN PROSECUTING ARSON CASES, CRIMINAL JUSTICE PERSONNEL MUST FIRST ESTABLISH CAUSE AND INTENT BECAUSE FIRE, A NATURAL PHENOMENON, IS OFTEN CAUSED BY ACCIDENT. HOWEVER, CAUSE, INTENT, AND MOTIVE (THE LATTER IS IMPORTANT TO ESTABLISHING INTENT) ARE DIFFICULT TO ESTABLISH SINCE FIRE DESTROYS MUCH EVIDENCE. MOREOVER, SINCE ARSONISTS MAY DISGUISE THEIR METHODS, MUCH EVIDENCE MAY BE MISLEADING. FIRESETTING IS EITHER MOTIVATIONAL OR MOTIVELESS: MOTIVATIONAL FIRESETTERS ARE AWARE OF THEIR REASONS, BUT THE MOTIVELESS, SUCH AS PYROMANIACS, ARE NOT. HOWEVER, MOTIVELESS FIRESETTERS DO NOT CAUSE MOST ARSON. ARSON IS GENERALLY DIVIDED AMONG FIVE CATEGORIES: ARSON TO CONCEAL OTHER CRIME, OFTEN A METHOD USED BY ORGANIZED CRIME; INSURANCE FRAUD; COMMERCIAL; RESIDENTIAL (INCLUDING AUTOMOBILE CRIME); AND PSYCHOLOGICAL (SUCH AS PYROMANIA AND FIRES CAUSED BY JUVENILES). IRRATIONAL FIRESETTING, TYPICALLY THE RESULT OF MENTAL OR EMOTIONAL DISTURBANCES, MAY BE DONE FOR SENSUAL EXCITEMENT, REVENGE, TO ATTRACT ATTENTION OR BOLSTER THE EGO, OR AS A RESULT OF PSYCHOSIS OR DELUSIONS. FURTHER, CHILDREN AND ADOLESCENTS SET MANY FIRES FOR MISCHIEF. HOWEVER, REVENGE OR A DESIRE TO PUNISH SEEMS TO UNDERLIE MOST ARSON MOTIVES. FOOTNOTES ARE INCLUDED.